An oxygen supply unit with a foldable rail section for mounting the complete unit in an aircraft has become known from U.S. Pat. No. 4,840,171 (corresponding to DE-A1 37,19,427). Such oxygen supply units are arranged in the ceiling structures of aircraft and are used to supply the passengers with the oxygen needed for respiration in the case of need. The oxygen supply unit consists of a container, in which a plurality of oxygen masks and an oxygen generator are arranged, and of a container door, which is pivotable around a joint and is used to close the container.
Foldable rail sections, which extend in parallel to the joint of the container door, and with which the complete oxygen supply unit can be suspended in a holder in the ceiling structure of the aircraft, are arranged at the front and rear edges of the container. The rail sections are used for the simple fastening of the oxygen supply unit in the ceiling structure, on the one hand, and, on the other hand, they also facilitate removal, because the complete oxygen supply unit can be removed from the ceiling structure without tools. Since the oxygen supply units are associated with the passengers and are therefore present on board in large numbers, especially in large-capacity aircraft, they must be optimized in terms of both minimal weight and the possibility of manufacture at low cost. On the other hand, parts subject to wear, e.g., the rail section, must be able to be replaced in a simple manner at the time of maintenance.
The rail sections are usually fastened to the container with a type of piano hinge on the container, with a bar pushed through as the axis of rotation. If the rail section is to be replaced, the bar must first be pulled out of the piano hinge, and the rail section must then be removed from the container. The joint of the container door consists of individual bearing blocks, which are screwed onto the edge of the container as separate components, and of a bar, pushed through, which acts as the axis of rotation for the container door. Besides fastening the container door, the bearing blocks also act as a stop in order to limit the pivoting stroke of the container.
It is disadvantageous in the prior-art oxygen supply unit that both the hinge for the rail sections and the joint of the container door with the bearing blocks require a plurality of individual parts, which is disadvantageous in terms of both the manufacturing costs and the weight of the device. In addition, replacement of the rail sections is made difficult by the fact that the bar forming the axis of rotation must be pulled out of the piano hinge.
West German Utility Pat. No. DE-GM 19,57,658 illustrates a hinge for the cover of a plastic box, wherein the hinge parts are made directly in one piece with the cover and the box, respectively, and consist of two slots at the edge of the cover, and semicircular tongues of the box extend into the said slots.
The manufacture of such a hinge is made difficult by the fact that the limiting webs of the slots on the cover are bent down at right angles, and have a bead, which is located between the limiting bars and acts as the fulcrum point for the hinge, only there, offset by a step from the flat surface of the cover. In addition, the prior-art hinge has no stop function for the pivoting stroke of the cover.